/**
 * 生成唯一标识符32位UUID
 * @return {String}
 */
export default function uuid() {
    var s = [];
    var hexDigits = '0123456789abcdef';
    for (var i = 0; i < 32; i++) {
        s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
    }
    s[14] = '4';  // bits 12-15 of the time_hi_and_version field to 0010
    s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1);  // bits 6-7 of the clock_seq_hi_and_reserved to 01
    // s[8] = s[13] = s[18] = s[23] = '-';
    var uuid = s.join('');
    return uuid;
}
  